Constant pressure variable displacement pump



April 1965 D. J. CAMERON ETAL 3,177,312

CONSTANT PRESSURE VARIABLE DISPLACEMENT PUMP Filed Feb. 11, 1963 FIG.4.

INVENTORS DONALD J.CAMERON RAYMOND L. ENSINGER JOHN E.SMITH ATTO R N EYS United States Patent C 3,177,812 CONSTANT PRESSURE VLE DIS- PLACEMENT PUMP Donald J. Cameron, Poway, Calif., and Raymond L.

Ensinger, Detroit, and John E. Smith, Rochester, Mich,

assignors to Holley Carburetor Company, Warren,

Mich, a corporation of Michigan Filed Feb. 11, 1963, Ser. No. 258,953 9 Claims. (Cl. 103-38) The present invention relates to fuel pumps and is a continuation-in-part application of our copending application U.S. Serial Number 51,192 entitled Constant Pressure Variable Displacement Pump which was filed on August 22, 1960, now abandoned. More specifically, this invention relates to a fuel pump capable of delivering fuel to a place of use at a constant pressure.

It is an object of the present invention to provide a fluid pump characterized by its simplicity, the economy with which it may be produced, and the efficiency with which it operates.

It is another object of the present invention to provide a pump capable of delivering a fluid such as fuel under a substantially uniform pressure on demand.

Still another object of the present invention is to provide a fuel pump of the type described in the preceding paragraphs characterized by an arrangement which includes a pumping chamber having a movable pumping element therein and mechanical means for driving said pumping element in pumping strokes against a spring and permitting the pumping element to move in suction strokes between the pumping strokes.

A further object of the present invention is to provide a fuel pump of the type described in the preceding paragraphs characterized by an arrangement which includes a pumping chamber having a movable pumping element therein, mechanical means for driving said pumping element in pumping strokes against a spring and permitting the pumping element to move in suction strokes between the pumping strokes, and check valves controlling the flow of fuel into and out of said chamber.

A still further object of the present invention is to provide a pump of the character described including a pumping chamber having a movable pumping element therein. mechanical means for driving said pumping element in pumping strokes in combination with a drive shaft having an eccentric portion and means associated therein for effecting movement of said mechanical means and reciprocation of said pumping element;

Another object of the present invention is to provide a pump of the character described including a pumping chamber having a movable pumping element therein, mechanical means for driving said pumping element in pumping strokes, said mechanical means including a flow comensating element for determining the magnitude of the pumping strokes, in combination with a drive shaft having an eccentric portion and means associated therein for effecting movement of said mechanical means and reciprocation of said pumping element.

Still another object of the present invention is to provide a pump of the character described including a pumping chamber having a movable pumping element therein, mechanical means for driving said pumping element in pumping strokes, said mechanical means including a flow compensating element for determining the magnitude of the pumping strokes, in combination with a drive shaft having an eccentric portion, means associated therein for effecting movement of said mechanical means and reciprocation of said pumping element, and check valves controlling the flow of fuel into and out of said chamber.

Other objects and features of the invention will become "ice apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is an elevational view partly in section taken on line 11 of FIGURE 3.

FIGURE 2 is a sectional view taken on line 2--2 of FIGURE 1. 7

FIGURE 3 is a top view of the invention.

FIGURE 4 is a perspective view of part of the actuating mechanism.

Pumps of the character described which embody the present invention are adaptable to a wide variety of uses and are particularly desirable for use with a pump which is required to deliver fuel at varying volume but at a substantially constant pressure. The construction of the pump will be explained in connection with but one of its many applications and after its construction for this purpose and in this connection is made known, its application to other specific uses and such modifications in the structure described necessary to meet any change in conditions caused thereby will be readily apparent to those skilled in the art.

The particular application of the present invention will be described in connection with an internal combustion engine of an automobile vehicle. Such a mechanical pump is operated by a eccentric mounted on a driven shaft. FIGURE 1 shows a pump designated by the numeral 1t whichis connected to a mounting bracket designated by the numeral 12. The pump 10 has a flange 14 which is connected to the mounting bracket 12 by means of a bolt 16 and nut 18. The pump 10 is of the constant pressure variable displacement type and includes the housing or casing 20. End caps 22 and 24 are provided so as to enclose the entire pumping mechanism in the housing 29. The shaft 26 has an eccentric 28 mounted thereon. The shaft 26 is adapted to be driven by an electric motor or the like so as to move the actuating or mechanical means in pumping strokes.

The pump 10 further includes a pumping chamber 39 having a cylinder in which a single piston 32 is adapted to move. 'An inlet check valve 34 is mounted in the inlet of the casing 20 and supplies fuel to the pumping chamber 30 when piston 32 is moved in its suction stroke. An outlet check valve 36 is mounted in the casing 20 between the pumping chamber 30 and the accumulator chamber 38 to transmit the fuel during the pumping strokes from the pumping chamber 30 to the accumulator chamber 38.

The accumulator chamber 38 is provided with a cylinder and is in direct communication with the outlet 40 provided in the casing 20.

Means are provided for maintaining the pressure of the fuel at the outlet 40 of the pump lit at a susbtantially constant pressure. The means include a fiow compensator or accumulator piston 42 which is movable in the cylinder provided in the accumulator chamber 3%. The accumulator piston 42 is spring biased to control the length of the stroke of the pumping piston 32. FIGURE 1 shows the accumulator piston 42 in a position which results in the maximum pumping stroke for the pumping piston 32.

A control housing portion 43 is provided in the easing 20 intermediate the pumping chamber 31 and the accumulator chamber 38 and is in communication with said chambers through the cylinders provided therein. The pumping piston 32 and the accumulator piston 42 close their respective cylinders to said housing portion 43 so as to seal said housing portion 43. The accumulator piston 42 includes ends having a cup-shape head 44 and an elongated cylindrical stem 46 which is adapted to telescope within the hub 48 provided in the housing portion 43. A spring 56 seats against the inner wall 52 of the housing portion 43 and engages a flange or spring seat 54 on the accumulator piston 42 to bias the accumulator piston 42 in a direction to determine the pressure at which the fuel is maintained in the accumulator chamber 33.

The compensator or accumulator piston 42 includes intermediate the stem 46 and the head 44 a pair of connecting members 56. The stem 46 and connecting members 56 constitute an extension of the accumulator piston 42. The extension is located in the control housing portion 43 and is adapted to move in a path transversely of the path of movement of the pumping piston 32. Interposed between the connecting members 56, which constitute part of the accumulator extension, is a U-shaped bracket 58 which is adapted to pivot on a pivot pin 66 carried by the extension as best illustrated in FIGURES l and 4. The pin 60 extends through the base 62 of the bracket 53, with the ends thereof being carried by the connecting members 56. The bracket 58 includes a pair of transversely extendin lever arms 64 at opposite ends of the base 62 which extend into the space between the pumping piston 32 and the eccentric driver 28. The lever arms 64 are not attached to the connecting members 56, but are provided with thrust transmitting abutments, abutment means, or surfaces 65 which are in contact with the pumping piston 32 to provide a one-way positive acting mechanical connection therebetween. The free ends of the lever arms 64 carry a pin 68 for mounting a roller 66 between the inner surfaces of the lever arms 64.

Interposed between the roller 66 and the eccentric driver 28 is a thrust transmitting lever or arm 70 which is mounted on a fixed pivot pin 72 located in the control housing portion 43 of the casing 20. The arm 70 is adapted to be moved upwardly, as viewed in FIGURE 1, by the eccentric driver 28 as will be subsequently explained so as to effect actuation of the pumping piston 32.

The pumping piston 32 has a pair of flanges 74 which extend into the control housing portion 43.. A roller 76 is interposed between the flanges 74 and includes a pair of annular flanges 77 at opposite sides thereof. A pin 78 extends through the flanges 74 and roller 76. A compression spring 84) biases the pumping piston 32 towards the eccentric driver 28 to maintain contact between the flanges 77 of roller 76 and the thrust transmitting abutments or surfaces 65 provided on the' lever arms 64.

It should be noted that the thrust'transmitting abutments or surfaces 65 provided on the lever arms 64 are mounted on the accumulator extension for movement in a path transversely of the path of movement of the pumping piston 32 in accordance with the transverse displacement of the accumulator piston 42. In addition, the abut-' ments 65 are movable by the arm 70 and eccentric driver 28 in paths which are substantially parallel to the path of movement of the pumping piston 32.

The operation is believed apparent from the foregoing description; but will be briefly reviewed. When the eccentric driver 28 falls away, the pumping piston 32 follows on its suction stroke with the spring 80 maintaining contact between the flanges 77 provided on the roller 76 of the pumping piston 32 and the abutments 65 provided on the lever arms 64. This results in fuel entering the pumping chamber 30 through the spring biased inlet check valve 34. When the eccentric driver 28 begins to move up through its second 180 degree rotation, the pumping piston 32 is mechanically moved upwardly in its pumping stroke by the mechanical lever 76 and results in fuel being discharged from the pumping chamber 36 through the outlet check valve 36 into the accumulator chamber 38. This is accomplished by the eccentric driver 28 moving the lever 70 upwardly with reference to the pivot pin 72 so as to'move the roller 66 and the lever arms 64 in the same direction about pivot 64 This thrust or motion in turn drives the pumping piston 32 in its pumping stroke against the spring it by means of the abutments 65 provided on the lever arms 64. When the pumping stroke occurs, the inlet check valve 34 is closed.

As the accumulator chamber 38 fills with fluid on a decrease in demand, it is necessary to decrease the stroke of the pumping piston 32 so as to result in a corresponding reduction in the volume of fuel delivered to the accumulator chamber 33. An increase in the volume of fuelin the accumulator chamber 38 acts on the piston head 44 against the spring 50. As the volume increases, the fluid force acting on the accumulator piston 42 overcomes the spring 59 and moves the accumulator piston 42 to the left, as viewed in FIGURE 1, to a position which will deliver the fuel at a lower rate.

As the accumulator piston 42 is moved to the left, the thrust transmitting abutments 65 provided on bracket 58 are also moved to the left. At such a time the pivot pin 66 is moved towards the fixed pivot pin 72 and as a result thereof the stroke of the pumping piston 32 is decreased.

When the volume of fuel in the accumulator chamber 38 is such that the accumulator piston 42 is moved to the left to a position where the axis of roller 66 and pin 68 is approximately directly above or in the same vertical plane as the axis of pin 72, no output motion is produced between the arm 70 and bracket 58 and hence, the stroke of the pumping piston 32 is zero. It can be seen that if no fuel is required, the stroke of the pumping piston 32 will go to zero and the pressure maintained substantially constant by the spring 56.

The movement of the acctunulator piston 42 between full and zero stroke positions is small. The head 44 of the accumulator piston 42, when at zero position, is shown in dotted lines in FIGURE 1.

At near full capacity, the stroke of the pumping piston 32 will be at maximum as will the total movement of the accumulator piston 42, and the pressure fluctuation will be maximum, its mgnitude being determined by the rate of spring 59 and the diameters of pistons 32 and 42 through one complete cycle of the eccentric 28. 7 While the pump disclosed herein has a particular application as a pump for liquid fuel, it is also adapted to pump any fluid including air. Appropriate sea-lings means are provided in the casing 20 to prevent leakage therefrom.

The drawing and foregoing specification constitute a description of constant pressure variable displacement pump in such full, clear, concise, and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. A constant pressure variable displacement pump comprising: a casing having a pumping chamber, an accumulator chamber in valved communication with the pumping chamber, and a control housing portion intermediate said chambers; a pumping piston having an axis mounted for linear movement in said pumping chamber for pumping fluid from the pumping chamber into the accumulator chamber on actuation thereof; an accumulator piston mounted for linear movement within said accumulator chamber to vary the volume thereof; an eccentric driver in said control housing portion; said accumulator piston having an extension in said control housing portion and movable with said accumulator piston transversely of the path of movement of said pumping piston; a bracket pivoted to said extension on one side of the axis of said pumping piston; thrust transmitting abutment means carried by said bracket and interposed between said pumping piston and said driver and having a one-way positive acting mechanical connection with said pumping piston; said abutment means being mounted on said bracket for movement in a path substantially parallel to the path of movement of said pumping piston to transmit thrust from said driver to said pumping piston and for transverse movement with said accumulator piston;

said abutment means being movable in said substantially parallel path a distance which varies in accordance with the position of said accumulator piston; said accumulator piston being responsive to the outlet pressure of said pump to control transverse displacement of said abutment means and thereby control outlet pressure by varying the length of the pumping stroke of said pumping piston.

2. A constant pressure variable displacement pump comprising: a casing having a pumping chamber, an accumulator chamber in valved communication with the pumping chamber, and a control housing portion intermediate said chambers; a pumping piston having an axis mounted for linear movement in said pumping chamber for pumping fluid from the pumping chamber into the accumulator chamber on actuation thereof; an accumulator piston mounted for linear movement within said accumulator chamber to vary the volume thereof; an eccentric driver in said control housing portion; said accumulator piston having an extension in said control housing portion and movable with said accumulator piston transversely of the path of movement of said pumping piston; a bracket pivoted to said extension on one side of the axis of said pumping piston; a thrust transmitting abutment on said bracket having a oneway positive acting mechanical connection with said pumping piston; an arm pivotally mounted in said control housing portion on the other side of the axis of said pumping piston and engageable With said bracket and said driver for transmitting thrust from said driver to said pumping piston through said bracket and thrust transmitting abutment; the distance between the pivot axes of said bracket and arm varying depending on the position of said accumulator piston, with the maximum distance corresponding to the maximum pumping stroke of said pumping piston and the minimum distance corresponding to the minimum pumping stroke; said accumulator piston being responsive to the outlet pressure of said pump to control transverse displacement of said abutment and thereby control outlet pressure by varying the length of the pumping stroke of said pumping piston.

3. A constant pressure variable displacement pump defined in claim 2 wherein the axis of said pumping piston is substantially perpendicular to the axis of said accumulator piston.

4. A constant pressure variable displacement pump defined in claim 2 wherein guide means are provided in said control housing portion for guiding the end of said accumulator extension remote from said accumulator chamber.

5. A constant pressure variable displacement pump defined in claim 2 wherein a roller is carried by the other end of said bracket having a surface in engagement with said arm for transmitting the thrust to said pumping piston.

6. A constant pressure variable displacement pump comprising: a casing having a pumping chamber, an accumulator chamber in valved communication with the pumping chamber, and a control housing portion intermediate said ohambers; a pumping piston having an axis mounted for linear movement in said pumping chamber for pumping fluid from the pumping chamber into the accumulator chamber on actuation thereof; an accumulator piston having an axis mounted for linear movement within said accumulator chamber to vary the voluine thereof; said pistons each having a portion closing their respective chambers to said control housing portion; pressure means in said control housing portion for urging said accumulator piston in a direction to decrease the volume gt the accumulator chamber and to maintain the fluid therein at a substantially constant pressure; said accumulator piston having an extension in said control housing portion and movable with said accumulator piston transversely of the path of movement of said pumping piston; an eccentric driver in said contnol housing portion spaced from said pumping piston; a bracket pivotally connected on one end to said accumulator extension on one side of the axis of said pumping piston; a thrust transmitting abutment on said bracket in operative juxtaposition to said pumping piston to provide a one-Way positive acting mechanical connection therebetween for moving said pumping piston in its pumping stroke; an arm pivotally' mounted on one end on a fixed pivot in said control housing portion on the other side of the axis of said pumping piston; the pivot connection of said bracket being movable towards and away from said fixed pivot in response to the movement of said accumulator to respectively decrease or increase the stroke of the pumping piston; said arm having sides engageable with said bracket and said driver to transmit a thrust from said driver to said bracket whereby said thrust transmitting abutment urges the pumping piston in its pumping stroke; and resilient means connected to the pumping piston for urging the pumping piston toward said abutment; said accumulator piston being responsive to the pressure of fluid in said accumulator chamber and to said pressure means to control transverse displacement of said abutment and thereby control the pressure in said accumulator chamber by varying the length of the pumping stroke of said pumping piston.

7. A constant pressure variable displacement pump defined in claim 6 wherein the axis of said pumping piston is substantially perpendicular to the'axis of said accumulator piston.

8. A'constant pressure variable displacement pump defined in claim 6 wherein guide means are provided in said control housing portion for guiding the end of said accumulator extension remote from said accumulator chamber.

9. A constant pressure variable displacement pump defined in claim 6 wherein a roller is carried by the other end of said bracket having a surface in engagement with said arm for transmitting the thrust to said pumping piston.

References Cited by the Examiner UNITED STATES PATENTS 1,724,156 8/29 Winton 103-153 1,813,078 7/311 -Nyrop 103-38 1,824,467 9/31 Darby 103-38 1,862,132 6/32 Adams 103-38 1,868,713 7/32 Miller 103-38 2,099,206 11/37 Hedbom 103-38 2,183,436 12/39 Towler et al. 103-38 2,191,552 2/40 Zimmermann 103-3 8 2,423,162 7/47 Summers 103-38 2,514,674 7/50 Schorn 103-38 2,604,855 7/52 Towler et al. 103-153 2,669,185 2/54 Tallis 103-38 2,783,652 3/57 Smith -1 74-110 2,819,678 1/58 'Nordell et a1. 103-150 FOREIGN PATENTS 463,894 12/16 France.

889,921 10/ 43 France.

915,525 7/54 Germany.

16,529 7/09 Great Britain.

LAURENCE v. EFNER, Primary Examiner. 

1. A CONSTANT PRESSURE VARIABLE DISPLACEMENT PUMP COMPRISING: A CASING HAVING A PUMPING CHAMBER, AN ACCUMULATOR CHAMBER IN VALVED COMMUNICATION WITH THE PUMPING CHAMBER, AND A CONTROL HOUSING PORTION INTERMEDIATE SAID CHAMBERS; A PUMPING PISTON HAVING AN AXIS MOUNTED FOR LINEAR MOVEMENT IN SAID PUMPING CHAMBER FOR PLUMPING FLUID FROM THE PUMPING CHAMBER INTO THE ACCUMULATOR CHAMBER ON ACTUATION THEREOF; AN ACCUMULATOR PISTON MOUNTED FOR LINEAR MOVEMENT WITHIN SAID ACCUMULATOR CHAMBER TO VARY THE VOLUME THEREOF; AN ECCENTRIC DRIVER IN SAID CONTROL HOUSING PORTION; SAID ACCUMULATOR PISTON HAVING AN EXTENSION IN SAID CONTROL HOUSING PORTION AND MOVABLE WITH SAID ACCUMULATOR PISTON TRANSVERSELY OF THE PATH OF MOVEMENT OF SAID PUMPING PISTON; A BRACKET PIVOTED TO SAID EXTENSION ON ONE SIDE OF THE AXIS OF SAID PUMPING PISTON; THRUST TRANSMITTING ABUTMENT MEANS CARRIED BY SAID BRACKET AND INTERPOSED BETWEEN SAID PUMPING PISTON AND SAID DRIVER AND HAVING A ONE-WAY POSITIVE ACTING MECHANICAL CONNECTION WITH SAID PUMPING PISTON; SAID ABUTMENT MEANS BEING MOUNTED ON SAID BRACKET FOR MOVEMENT IN A PATH SUBSTANTIALLY PARALLEL TO THE PATH OF MOVEMENT OF SAID PUMPING PISTON TO TRANSMIT THRUST FROM SAID DRIVER TO SAID PUMPING PISTON AND FOR TRANSVERSE MOVEMENT WITH SAID ACCUMULATOR PISTON; SAID ABUTMENT MEANS BEING MOVABLE IN SAID SUBSTANTIALLY PARALLEL PATH A DISTANCE WHICH VARIES IN ACCORDANCE WITH THE POSITION OF SAID ACCUMULATOR PISTON; SAID ACCUMULATOR PISTON BEING RESPONSIVE TO THE OUTLET PRESSURE OF SAID PUMP TO CONTROL TRANSVERSE DISPLACEMENT OF SAID ABUTMENT MEANS AND THEREBY CONTROL OUTLET PRESSURE BY VARYING THE LENGTH OF THE PUMPING STROKE OF SAID PUMPING PISTON. 